Spirit level with translucent spirit vial housings

ABSTRACT

A spirit level of elongated structure for determining plumb and horizontal orientations having spirit vial units at longitudinally spaced intervals thereof is provided. The spirit level frame comprises an elongated channel having parallel side walls and a connecting web extending perpendicularly between the side walls. The side walls form a recess which is adapted to receive the spirit vial units. At least one of the spirit vial units has a pair of spirit vials disposed perpendicularly to each other to permit simultaneous reading of both spirit levels to determine plumb. The spirit vial unit has a translucent housing for maintaining the vials in the recess. The housing has a transparent window to enable simultaneous reading of both the vials from a lateral position. The remaining portion of the translucent housing facilitates ease of reading by providing additional light to the vials while preventing the viewer from confusing other structure within the housing with said vials.

United States Patent [1 1 Ostrager [4 1 Apr. 3, 1973 [54] SPIRIT LEVELWITH TRANSLUCENT Primary Examiner-Leonard Forman SPIRIT VIAL HOUSINGSAssistant ExaminerDennis A. Dearing [76] Inventor: Seymour A. Ostrager,1188 Grand Att0mey cae8ar Rwlse Bernstein & Cohen I Concourse, Bronx,N.Y. [57] ABSTRACT [22] Flled: 1970 A spirit level of elongatedstructure for determining [21] Appl. No.: 84,040 plumb and horizontalorientations having spirit vial units at longitudinally spaced intervalsthereof is pro- 521 US. Cl. ..,....33/348, 33/383, 33/384 vided' The Plevel mprises [51] Int Cl G01: 9/32 Golc 9/30 channel having parallelside walls and a connecting t 58 l i h n web extending perpendicularlybetween the side walls. 1 d 0 Se-arc 33/211 214 The side walls form arecess which is adapted to [56] References Cited receive the spirit vialunits. At least one of the spirit vial units has a pair of spirit vialsdisposed perpendicu- UNITED STATES PATENTS larly to each other topermitsimultaneous reading of 7 both spirit levels to determine plumb. Thespirit vial g "33/207 unit has a translucent housing for maintaining thevials ll77l31 3/1916 New in the recess. The housing has a transparentwindow to 3:071:863 1/1963 enable simultaneous reading of both the vialsfrom a 1,435,365 11/1922 Zieman lateral position. The remaining portionof the translu- 2,727,3l4 1-2/1955 Dossie,... cent housing facilitatesease of reading by providing 3,088,216 5/1963 Jesonis additional lightto the vials while preventing the ,235 3/1950 Schultes viewer fromconfusing other structure within the hous- 3,435,533 4/1969 Whitfield...ing with said i 1,908,496 5/1933 Hunter ..33/2ll 9 Claims,9 DrawingFigures SPIRIT LEVEL WITH TRANSLUCENT SPIRIT VIAL HOUSINGS Thisinvention relates generally to spirit levels and more particularly to aspirit level which includes spirit vial units to enable determination ofplumb and at least one spirit vial unit for determining the horizontalorientation of a surface.

Conventional levels of elongated structure have, in the past, beeninadequate since they were incapable of determining plumb with only onereading of the level. That is, the level was required to be placedagainst a first surface of an object which is desired to be disposedvertically and then after the object was made vertical in the firstdirection, the level was required to be placed at a dispositiontransverse to the first location of the level so that the verticalnessof the object could be determined in a second orientation.

The Dossie U.S. Pat. No. 2,727,314 disclosed a combination spirit leveland plumb which enables simultaneous reading of a pair of vials for thedetermination of plumb. However, the Dossie structure, while importantfor the concept it introduced, has never been feasible to producecommercially. The reason for the impracticality of the level shown inthe Dossie patent is that the cost of imbedding spirit vials in a spiritlevel rail such as shown therein and the cost of accurately positioningthe vials in the structure were prohibitive.

In my copending application Ser. No. 883,893, filed Dec. 10, 1969, thereis disclosed a spirit level of elongated structure having spi'rit vialunits for determining plumb wherein the frame of the level is of suchsimple channel construction that it can be produced by extrusion. Theembodiment disclosed in the aforesaid copending application has broughtdown the cost of the item considerably because'of the savings in thechannel construction. However, the cost of producing the plumb spiritvial units had not been considerably reduced. Moreover, in dark corners,the spirit vials were difficult to read.

It is therefore an object of this invention to overcome thedisadvantages found in the earlier inventions in this field and toprovide a new and improved spirit level.

Another object of the invention is. to provide a new and improved spiritlevel having spirit vial units mounted at longitudinally spacedintervals which are easily readable and easily accessible to the userthereof.

Another object of the invention is to provide a new and improved spiritlevel of elongated structure having spirit vial units which fit withinrecesses provided within the frame and are easily mounted therein.

Yet another object of the invention is to provide a new and improvedspirit level of elongated structure wherein the housings for said spiritvial units are comprised of modular construction which are easily fittedtogether and provide adjustability for alignment of the vials withrespect to the horizontal and vertical surfaces of the level frame.

Yet another object of the invention is to provide a new and improvedspirit level wherein the spirit level housings are comprised oftranslucent material to enable increased'light to strike the surface ofsaid spirit vials to enable easier reading thereof.

These and other objects of the invention are achieved byproviding a.spirit level of elongated structure having spirit vial units atlongitudinally spaced-internals' thereof. The spirit level framecomprises an elongated channel having parallel side walls and aconnecting web extending perpendicularly between said side walls to forma recess which is adapted to receive the spirit vial units. At least oneof the spirit vial units has a plurality of spirit vials disposedperpendicularly to each other to permit simultaneous reading of bothspirit vials to determine plumb. The spirit vial unit has a translucenthousing for maintaining the vials in the recess. The housing has atransparent window to enable simultaneous readings of both the housingsfrom a lateral position. The translucent remainder of the housingfacilitates ease of reading.

Other objects and many of the attendant advantages of this inventionwill be readily appreciated as the same becomes better understood byreference to the following detailed description when considered inconnection with the accompanying drawings wherein:

FIG. 1 is a perspective view of a spirit level embodying the inventionshown in use for determining the plumb of an object;

FIG.'2 is a top plan view of the spirit level in use;

FIG. 3 is an enlarged fragmentary front elevational view of the level;

FIG. 4 is an enlarged sectional view taken along the line 44 in FIG. 3;

FIG. 5 is an enlarged exploded side elevational view of the housing andspirit holding members to show the construction of the spirit vial unitembodying the invention;

FIG. 6 is an enlarged top plan view of a holder for one of the spiritvials taken along the-line 6-6 in FIG.

FIG. 7 is an enlarged front elevational view of the holder taken alongthe line 7-7 in FIG. 5;

FIG. 8 is an enlarged sectional view taken along the line 8-8 in FIG. 3;and

FIG. 9 is a sectional view taken along the line 99 in FIG. 8 with afragmentary portion of the frame shown in elevation for purposes ofclarity.

Referring now in greater detail to the various figures of the drawingwherein like reference numerals refer to like parts, a spirit level withtranslucent spirit vial holdings is shown generally at 20 in FIG. 1.

Spirit level 20 basically comprises a frame 22, a pair of similar spiritvial units 24 mounted at each-endof the level for determining plumb anda spirit vial unit 26 which is preferably located-at the center of theframe and is used for determining the horizontal orientation 1 of theside walls of the frame 22.

Frame 22 is of elongated structure and is preferably comprised ofextruded aluminum-or aluminum alloy. Frame 22 is basically U-shaped incross-section and includes a pair of side walls 28 and 30 and a thinconnecting transversely extending web 32.

Side wall 30 includes a flange extension 34 which projects beyond theexposed surface of web.32. The angular surface of the wall formed byprojection 34 and the outer surface of the web 32 is a right angleformed with respect to each other to provide the simultaneous gauging oftwo perpendicularly disposed vertical surfaces or horizontal andvertical surfaces depending upon the orientation of the elongated frame;

For example, as shown in FIGS. 1 and 2, a vertically extending object,such as a verticalstandard, having a pair of planar vertically extendingsurfaces 38 and 40 which extend at right angles with respect to eachother can be tested for plumb with spirit level 20. By placing the levelwith the projection 34 against one of the vertical surfaces 40 and theouter surface of web 32 against the other of the vertical surfaces 38,the level 20 is enabled to determine plumb.

The spirit vial unit 24 which is at the upper end of the frame in thevertical disposition is utilized to determine plumb. As will be seen ingreater detail hereinafter, the two spirit vials provided in the spiritvial units 24 are coincidentally viewed in order to determine the plumb.It should also be noted that the outer surface of web 32 may be placedagainst vertical surface 40 and projection 34 placed against surface 38of the object 36 and the other of the spirit vial units is utilized todetermine the plumb of object 36.

One of the spirit vial units 24 and the components thereof which areused to determine plumb are best seen in FIGS. 4 through 9. As seentherein, the spirit vial units 24 include a housing 42, a holder 44 formounting a first spirit vial 46, a second holder 48 for mounting asecond spirit vial 50, and a holder 52 for a mirror 54 whichis securedthereto.

The housing 42 and holders 44, 48 and 52 are each preferably comprisedof a clear or transparent high impact resistant thermoplastic such asLexan. The outer surface of housing 42 is predominantly translucent as aresult of having a corrugated texture so that it is not transparent fromthe outside looking in. The holders are transparent, however, to enablemaximum light transmission through the various parts of unit 24 to aidin reading of the vials.

The housing 42 basically comprises a planar end wall 56, a planar frontwall 58, a pair of planar side walls 60 and a diagonally extending endwall 62. As best seen in FIG. 4, the housing 42 fits within the recessof the frame 22 formed by walls 28 and 30 and web 32. The side walls 60of the housing 42 fit snugly within the inner surfaces of walls 28 and30.

As best seen in FIG. 8, mounting wall 70 includes a rectangular notch oropening 72 which, as will hereinafter be seen, accommodates holder 44.The wall 70 also includes an enlarged cylindrical portion 72 whichincludes an opening or bore which extends transversely to the front wall58 of the spirit vial unit 24. The bore of enlarged cylindrical portion74 of mounting wall 70 acts to receive a threaded fastener for securingthe spirit vial unit 24 to the frame 22.

Mounting wall 66 also includes a rectangular slot 76 which extendsparallel to wall 56 and which includes diagonally extending edges whichflare outwardly towards end wall 56. Diagonal walls of the slot 76 actto receive a dovetail-shaped projection 78 of the mirror holder 52.

As best seen in FIG. 9, the mounting wall 68 extends from the left (asshown) side wall 60 of the spirit vial unit 24 to a point approximatelytwo-thirds of the distance towards the right (as shown) side wall 60.The mounting wall 68 is terminated at a flange wall 78 which extendsparallel to side wall 60 and transversely to mounting wall 68. Acylindrical projection 80 which extends transversely to the front wall58 is connected to the walls 68 and 78 via a pair of intermediate walls82 and 84. Wall 82 extends between the projection 80 and wall 68parallel to wall 78 and intermediate wall 84 extends between projection80 and wall 78 parallel to the wall 68.

Cylindrical projection 80 and end walls 82 and 84 extend to the samedepth from the front wall 58 as does the cylindrical portion 74 ofmounting wall 70. Mounting wall 66 and mounting wall 68 each include anotch or rectangular cut-out 86 which enables reception and/oraccommodation of the holder 44.

As best seen in FIGS. 8 and 9, the diagonal end wall 62 includes arectangular slot 88 which accommodates The depth of the housing 42 issubstantially equal to the depth of the recess formed between walls 28and 30 and web 32 of the frame 22. Thus, the front wall 56 issubstantially flush with the outermost edge of side walls 28 and 30 ofthe frame.

Front wall 58 and side wall 60 extend transversely to end wall 56 withwalls 60 extending transversely to front wall 58. Thus, walls 60 and 58form a U-shaped channel which is terminated normally at end wall 56 anddiagonally at end wall 62.

End wall 56 includes a flange-like projection 64 which extends below thebottom of side wall 60 and laterally beyond side wall 60 so that, asseen in FIGS. 8 and 9, the end wall 56 is flush with the edges of sidewalls 28 and 30 and web 32 of the frame 22. Thus, projection 64 isU-shaped and extends around the sides and bottom ofthe spirit vial unit24.

Spaced inwardly of and parallel to end wall 42 is a first mounting wall66. Spaced further inwardly from mounting wall 66 and also parallel towall 56 is a second mounting wall 68. Wall 66 extends transverselybetween side walls 60 of the spirit vial unit 24. A third mounting wall70 extends transversely between mounting wall 66 and end wall 56.

a portion of holder 48 to enable alignment of the vial 50 with respectto the frame 22.

The left side wall 60, as seen in FIG. 9, includes a rectangular notchor cut-out 90 which is utilized to accommodate holder 44. The right sidewall 60, as seen in FIG. 9, includes a U-shaped slot 92 which is bestseen in FIG. 4, and which is adapted to receive a projection on theholder 48 for vial 50.

I-Iolder 44 is best seen in FIGS. 5 and 9 and basically comprises arectangular planar base 94 having a peripheral skirt 96 which extendstransversely to the base 94 around the entire periphery thereof andprojects away from the front wall 58 of the spirit vial unit housing 42.One portion of skirt 96 includes a U- shaped projection 98 whichincludes a laterally extending projection or flange 100. As best seen inFIG. 5, the skirt 96 also includes a pair of elongated projections 102which have knurled ends 104. As will hereinafter be seen, theprojections 102 with the knurled ends 104 thereof act to enablealignment of the vial 46 with respect to the frame 22 of the level 20.

As best seen in FIG. 9, a pair of tabs 106 are provided on holder 44which extends from opposite sides of skirt 96 in a lateral directiontowards end walls 56 and 62. As best seen in FIG. 9, each of the tabs106 includes an opening 108 which extends through the tabs 106 andaccommodates passage of the securement means for fixing the spirit vialunit 24 to the frame 22.

Five generally cylindrical pins extend transversely to rectangular base94 towards the front wall 58 of the housing 42 and in a directionopposite that of the skirt 96 with respect to the planar base 94. Pins110 act to embrace and maintain the spirit vial 46 within the spiritvial unit 24. As best seen in FIG. 8, the housing 42 includes a pair ofgenerally cylindrical pins 1 12 which extend transversely to theinnermost surface of front wall 58 and abut at their free ends the sidewall of the vial 46. Pins 110 and 112, thus, maintain via] 46 againstbase 94 in a fixed position within the housing 42 when the spirit vialunit 24 is secured within the frame 22.

As best seen in FIGS. 5 and 9, the holder 44 is assembled to the housingby laying the base 94 within the mounting walls 66 and 68 so that thetabs 106 extend through the cut-outs 86 in the walls 66 and 68 andflange 100 rests in the rectangular notch 90 in side wall 60. Theopenings 108 of the tabs 106 are also disposed over the bores of thecylindrical portion 74 of the wall 70 and cylindrical projection 80 sothat threaded fasteners 114 can be passed through the openings 108 andsecured in the bores of the cylindrical projection.

Holder 48 for spirit vial 50 in each of the spirit vial units 24 is bestseen in FIGS. 5 and 9. Holder 48 basically comprises a generallyrectangular planar base 116. On a first lateral surface of the base 116,a planar projection 118 is provided having a pair of straight edges 120which are connected together by a semi-circular or arcuate edge 122. Theprojection 118 is elongated and is parallel to the outer surface ofplanar base 116 and extends in a direction generally parallel to vial50. The projection 120 extends to and is terminated at an arcuate edge124 which is coextensive with the edge of the planar base 1 16.

Extending from the opposite surface of the planar base 116 are a pair ofprojections 126 which extend transversely to the base 116 and which abutthe ends of the spirit vials 50. A second pair of projections 128 whichextends substantially parallel to projections 126 are provided formaintaining the spirit vial 50 against a third pair of projections 130which are provided on the opposite lateral sides thereof.

The projections 130 are supported bya wall 132 which extends parallel tothe projections 130 and transversely to the planar base 116. An arm 134is also provided on the holder 48 which extends laterally of base 116but parallel to the plane of base 116. Arm 134 includes a diagonallyextending end or edge 136 which is best seen in FIG. 5 and FIG. 7 and isknurled. The knurled edge 136 projects into opening 88 of the diagonalwall 62 and enables the adjustment of the alignment of the vial 50 withrespect to the frame 22.

As best seen in FIG. 9, when the holder 48 is assembled to the housing42 of the spirit vial unit 24, the projection 118 fits within opening 92of side wall 60 of housing 42. The arm 134 projects into opening 88 andthe spirit vial 50 is maintained in place between the projections 128,126, 130 and flange wall 78.

The mirror holder 52 is best seen in FIGS. 8 and 9. The holder 52basically comprises a rectangular base 138 which has on one side thereofa triangular wall 140 and on one end thereof a rectangular wall 142.Wall 142 includes a dovetailed projection 144 which extendslongitudinally thereof and, as set forth above, is adapted to fit in theslot 76 of wall 66. Base 138 is planar and extends transversely to thewall and diagonally with respect to wall 142. On the other side of base138, with respect to wall 140, a rectangular mirror 154 of the same sizeas base 138 is secured thereto by a suitable adhesive. The mirror holder52 is secured to the housing 42 by pressing the dovetailed projection142 within slot 76. The holder is maintained in place between the frontwall 58 and the web 32 of the frame when the housing 42 is secured tothe frame 22.

Each of the spirit vial units 24 provided at each end of the level frame22 is identical and tits into the recess formed by the walls 28 and 30and the web 32. The web 32 includes, as best seen in FIG. 4, a knurledsurface at 144 adjacent and abutting the arcuate edge 124 of theprojection 122 of holder 48 when the holder is disposed within slot 92and unit 24 is assembled on the frame 22. It should be noted that theknurled surface 144 is provided on the web 32 of the level 20 adjacenteach of the holders 48 in the two spirit level units 24.

As best seen in FIGS. 3 and 9, a rectangular opening 146 is providedbelow and adjacent to the spirit vial unit 46 in the web 32 at each endof the level. As best seen in FIGS. 8 and 9, the projections 102 ofholder 44 extend through the opening 146 in the web to enable manualadjustment of the alignment of the vial 46 with respect to the levelframe 22.

That is, referring to FIG. 5, after each of the holders 44 and 48 forthe vials 46 and 50, respectively, and the holder 52 for the mirror areplaced in the housing 42,-

fasteners 114 are threadedly engaged in the bores of the cylindricalportion 74 of wall 70 and the cylindrical projection 80. Just prior tothe final turns of the fasteners 114 which tighten the fasteners for thefinal securement of the spirit vial unit 24 to the frame, arm 134 ofholder 48 is rotatable in the direction of arrows 148 in order to enablealignment of the spirit vial 50 so that bubble 150 is between lines 152of the vial 50 when the end wall 56 is horizontally oriented. That is,

'by rotation of arm 134 of the holder 48, the spirit vial 50 is rotatedas indicated by arrows 154 in FIG. 8.

It should be noted that slot 92 in side wall 60, as best seen in FIG. 4,is wider than the projection 122 so that the edge 122 of the projectionrotates within the arcuate end of slot 92. The extra width of the slotenables the rotation of the projection 118 with respect to the slot.

After the vial 50 has been oriented properly with respect to the frame,the orientation of vial 46 is checked with respect to the frame.

When the end wall 56 is horizontally oriented, the bubble 150 of vial 46should be between lines 152. Thus, if the bubble 150 is not so orientedin vial 46, the projections 102 are engaged at the knurled surfacesthereof so that the holder 44 is manipulated until the bubble 150 isdisposed within lines 152. It should be noted that the openings 108 inthe tabs 106 are large enough with respect to the cross-section of thefasteners 114 that relative movement can be obtained. After each of thespirit vials 46 and 50 are disposed properly with respect to the frame,the fasteners 114 are tightened and the holders 44 and 48 are, thus,locked securely in place to prevent further rotation of the spirit vials46 and 50 with respect to the frame.

The spirit vials 46 and 50 extend transversely with respect to eachother so that, effectively, the vial 46 is utilized to determine thevertical orientation of the side walls 28 and of the frame and thespirit vial 50 is utilized to determine the vertical disposition of theweb 32 of the frame. Of course, when both spirit vials have theirbubbles within lines 152, the level is vertically disposed.

Mirror 54, as best seen in FIG. 8, enables a lateral view of the spiritvial 50 by enabling the viewer to view the vial along the line of sightindicated by the arrows 156 therein. As best seen in FIG. 3, the frontwall 58 includes a transparent portion or window 160 which acts as awindow to enable viewing of both the spirit vials 46 and 50. It shouldbe noted that the reflected image of vial 50 via mirror 54 enables theviewing of the spirit vial 50 simultaneously with the spirit vial 46.The

' remainder ofthe housing 24 is translucent only because of thecorrugated texture of the outer surface of the spirit vial housing 42about the window 160. As best seen in FIG. 1, the web 32 includes a pairof elongated rectangular openings 162 which are provided between each ofthe spirit vial units 24 and the spirit vial units The spirit vial unit26 is preferably constructed as shown in my copending application Ser.No. 837,467 which was filed on June 30, l969. The spirit vial unit 26includes a housing 164 for a pair of spirit vials 166 and 168. Thedetails of the construction of the housing and the holding units for thespirit vials 166 and 168 are shown in my aforementioned ApplicationSerial No. 837,467. Both of the spirit vials 166 and 168 may be adjustedwith respect to the side walls 28 and 30 of the frame 22.

Spirit vial 166 is utilized to determine the horizontal orientation ofside wall 30 and spirit vial 168 is provided to determine the horizontalorientation of side wall 28. That is, when side wall 28 is provided ontop of a horizontal surface, the vial 168 should have its bubbledisposed within the lines and similarly when side wall 30 is placed ontop of a horizontal surface, the bubble within vial 166 should bebetween the lines.

The housing 164 of spirit vial unit 26 is also made with a corrugatedtextured outer surface so that the housing is translucent about theperiphery of the window 170 provided on each side of the spirit vialunits 166 and 168.

The window 170 is transparent and one is provided on each side of thespirit vials 166 and 168. A circular opening is provided in the web 32which is aligned with windows 170 and is the same size as the windows.The opening in the web 32 enables light to come through the other sideto facilitate the reading of the spirit vials 166 and 168 as well as toenable the spirit vials to be read from both sides of the web 32.

The provision in the spirit vial units 24 of a translucent housing andtransparent holders enables light to be transmitted readily through thehousing and the various components holding the spirit vials so thatmaximum lighting is provided to the spirit vials to enable visibilitythereof. The window 160 is provided in the spirit vial units onlyadjacent to the mirror 54 and spirit vial 46 and the remainder of thehousing inhibits viewing of the various organization of componentswithin the housing 42. Thus, the vials are not confused with theremaining components and readability of the spirit vials is, therefore,not difficult.

The knurled surface on the web 32 adjacent the projection 118 of holder48 firmly secures the holder 48 against rotation by inadvertent brushingagainst the knurled surface 136 of arm 134 when the spirit vial unit hasbeen firmly tightened to the frame 22.

The construction of the various holding units and the housing 42 of thespirit vial unit 24 also facilitates easy molding of the variousportions and facilitates construction thereof and thereby additionallylowers costs in producing the spirit level embodying the invention bydecreasing the time required for construction.

Without further elaboration, the foregoing will so fully illustrate myinvention that others may, by applying current or future knowledge,readily adapt the same for use under various conditions of service.

What is claimed as the invention is:

1. in a spirit level of elongated structure having spirit vial units atlongitudinally spaced intervals thereof, a spirit level frame comprisingan elongated channel having parallel sidewalls and a connecting webextending perpendicularly between said sidewalls, said sidewalls forminga recess adapted to receive spirit vial units, at least one of saidspirit vial units having a plurality of spirit vials disposedperpendicularly to each other to permit simultaneous reading of bothspirit vials to determine-plumb, each of said vials being mounted in acient light to enter said housing to facilitate ease of reading, saidweb including an opening through which means for adjusting the first ofsaid spirit vials extends, said housing further including an opening topermit access to the means for adjusting the second of said spiritvials, said housing including an end wall which is mounted flush againstthe ends of said sidewalls and said connecting web.

2. In a spirit level of elongated structure, a spirit level framecomprising an elongated channel having parallel side walls and aconnecting web extending perpendicularly between said side walls toreceive a spirit vial unit, said spirit vial unit having a plurality ofspirit vials disposed perpendicularly to each other to permitsimultaneous readings of both spirit vials to determine plumb, aprojecting member extending beyond the outer surface of said web andproviding with said surface of the web at least one right angle corner,whereby adjacent surfaces of said web and projecting member are adaptedfor collective engagement with two perpendicularly disposed verticalsurfaces and with adjacent perpendicularly disposed and verticalsurfaces, said spirit vial unit including a housing and a pair ofholders for said vials, said holders each being individually adjustableso that each vial is adjustable insaid side walls having a slottedopening therein which extends transversely to the web of said frame, the

holder for the first of said vials having a lateral projection forinsertion in said slotted opening, said opening being larger than thewidth of said projection so that the disposition of said holder can beadjusted with respect to said frame.

3. The spirit level of claim 2 wherein the holder for the other of saidvials includes a planar base having a pair of depending projections,said web of said frame having an opening for receiving said projectionsto enable adjustment of said holder for the other of said vials.

4. The spirit level of claim 2 wherein said holder for said first vialhas an integral elongated arm terminated in a diagonal knurled edge,said housing having a diagonally extending end wall including an openingtherein to accommodate the end of said arm so that said first vial isadjustable by manually engaging said knurled end. i

5. The spirit level of claim 2 wherein the outer surface of said housingis translucent and includes a transparent window adjacent said vials.

6. The spirit level of claim 2 wherein said holders are transparent tofacilitate transmission of light through said housing to said vials.

7. The spirit level of claim 2 wherein said spirit level includes a pairof said spirit vial units, said spirit vial units being provided on eachend of said frame.

8. The spirit level of claim 7 wherein said spirit level furtherincludes a spirit vial unit centrally located on said frame, saidcentrally located spirit vial unit including at least one via] fordetermining horizontal orientation of said spirit level frame.

9. The spirit level of claim 2 wherein said web includes a knurledsurface adjacent said projection so that said holder is fixed betweensaid knurled surface of said web and said slotted opening when saidspirit vial unit is tightly secured to said frame.

1. In a spirit level of elongated structure having spirit vial units atlongitudinally spaced intervals thereof, a spirit level frame comprisingan elongated channel having parallel sidewalls and a connecting webextending perpendicularly between said sidewalls, said sidewalls forminga recess adapted to receive spirit vial units, at least one of saidspirit vial units having a plurality of spirit vials disposedperpendicularly to each other to permit simultaneous reading of bothspirit vials to determine plumb, each of said vials being mounted in alight transmissive holder, said holder including light transmissivemeans for adjusting said holder, said spirit vial unit having atranslucent housing for maintaining said vials in said recess, saidhousing having a transparent window to enable simultaneous readings ofboth of said vials from a lateral position, said translucent remainderof said housing obscuring the holder and adjusting means for one of saidvials, yet enabling sufficient light to enter said housing to facilitateease of reading, said web including an opening through which means foradjusting the first of said spirit vials extends, said housing furtherincluding an opening to permit access to the means for adjusting thesecond of said spirit vials, said housing including an end wall which ismounted flush against the ends of said sidewalls and said connectingweb.
 2. In a spirit level of elongated structure, a spirit level framecomprising an elongated channel having parallel side walls and aconnecting web extending perpendicularly between said side walls toreceive a spirit vial unit, said spirit vial unit having a plurality ofspirit vials disposed perpendicularly to each other to permitsimultaneous readings of both spirit vials to determine plumb, Aprojecting member extending beyond the outer surface of said web andproviding with said surface of the web at least one right angle corner,whereby adjacent surfaces of said web and projecting member are adaptedfor collective engagement with two perpendicularly disposed verticalsurfaces and with adjacent perpendicularly disposed and verticalsurfaces, said spirit vial unit including a housing and a pair ofholders for said vials, said holders each being individually adjustableso that each vial is adjustable independently of the other of saidvials, and a mirror, said mirror being mounted adjacent a first of saidvials, said housing having a pair of side walls which are interposedbetween and abut said side walls of said frame, a first of said sidewalls having a slotted opening therein which extends transversely to theweb of said frame, the holder for the first of said vials having alateral projection for insertion in said slotted opening, said openingbeing larger than the width of said projection so that the dispositionof said holder can be adjusted with respect to said frame.
 3. The spiritlevel of claim 2 wherein the holder for the other of said vials includesa planar base having a pair of depending projections, said web of saidframe having an opening for receiving said projections to enableadjustment of said holder for the other of said vials.
 4. The spiritlevel of claim 2 wherein said holder for said first vial has an integralelongated arm terminated in a diagonal knurled edge, said housing havinga diagonally extending end wall including an opening therein toaccommodate the end of said arm so that said first vial is adjustable bymanually engaging said knurled end.
 5. The spirit level of claim 2wherein the outer surface of said housing is translucent and includes atransparent window adjacent said vials.
 6. The spirit level of claim 2wherein said holders are transparent to facilitate transmission of lightthrough said housing to said vials.
 7. The spirit level of claim 2wherein said spirit level includes a pair of said spirit vial units,said spirit vial units being provided on each end of said frame.
 8. Thespirit level of claim 7 wherein said spirit level further includes aspirit vial unit centrally located on said frame, said centrally locatedspirit vial unit including at least one vial for determining horizontalorientation of said spirit level frame.
 9. The spirit level of claim 2wherein said web includes a knurled surface adjacent said projection sothat said holder is fixed between said knurled surface of said web andsaid slotted opening when said spirit vial unit is tightly secured tosaid frame.